This application is based on and claims priority under 35 U.S.C. xc2xa7119 with respect to Japanese Application No. 11(1999)-310224 filed on Oct. 29, 2000, the entire content of which is incorporated herein by reference.
The present invention is generally directed to a vehicle seat. More particularly, the present invention pertains to a reclining angle adjustment system having a pair of seat reclining devices provided at laterally opposite sides of a vehicle seat for adjusting the reclining angle of the seat-back relative to the seat-cushion.
One type of reclining angle adjustment system for a vehicle seat is disclosed in U.S. Pat. No. 4,541,672 granted to Fukuta et al. This reclining angle adjustment system includes a pair of seat reclining devices provided at laterally opposite sides of a seat and a connecting mechanism that operatively connects the devices. The connecting mechanism is designed to include an amount of play to prevent one of the reclining devices from being half-locked due to mutual interference between the reclining devices when the other of the reclining devices is in the locked condition. On the other hand, this play in the connecting mechanism may cause a problem in that when the other reclining device is released by manipulating an operation lever, the resulting releasing movement of one of the reclining devices becomes delayed or, in a worst case scenario, a malfunction occurs. To avoid such a serious problem, the known reclining angle adjustment system is constructed so that the lock release mechanism of the reclining device at the driven side is structured to release the locked condition by less of an amount of operation which compensates for the play and so both of the reclining devices are made to be substantially simultaneously in the releasing locked condition.
However, with the known reclining angle adjustment system described above, both of the lock releasing mechanisms are unsymmetrical in the lateral direction, which results in the adjustment of the reclining angle being limited to operate at one side of the seat. Thus, a need exists for reclining angle adjustment system that makes it possible to adjust the reclining angle of the seat-back from either side of the seat, especially with bench type seats or seats having a relatively long lateral dimension.
One aspect of the present invention involves a seat reclining angle adjustment mechanism that includes a pair of seat reclining devices provided at laterally opposite sides of a seat device having a seat cushion member and a seat back member, with each of the seat reclining devices having a lock mechanism which locks the seat back member in a position relative to the seat cushion member and upon release allows the seat back member to be tilted in different angular positions with respect to the seat cushion member. A connecting shaft connects the lock mechanism of each of the seat reclining devices in a mutually operative manner, and an operating mechanism is connected to the connecting shaft for effecting operation of the lock mechanisms.
According to another aspect of the invention, a seat reclining angle adjustment device includes a pair of seat reclining devices provided at laterally opposite sides of a seat having a seat cushion member and a seat back member, with each of the seat reclining devices including a lock mechanism which locks the seat back member in position relative to the seat cushion member and upon release allows the seat back member to be tilted in different angular positions with respect to the seat cushion member. A connecting shaft connects the lock mechanism of both seat reclining devices in a mutually operative manner, and a pair of operating levers are positioned at opposite sides of the seat. A pair of connecting rods are provided, each of which is connected to the connecting shaft and to one of the operating levers for transmitting operating movement of either one of the operating levers to the connecting shaft to effect a release of the locking mechanism of both seat reclining devices.
In accordance with a further aspect of the present invention, a vehicle seat reclining angle adjustment device includes a pair of seat reclining devices adapted to be positioned at laterally opposite sides of a vehicle seat having a seat cushion member and a seat back member, with each of the seat reclining devices including an upper arm adapted to be connected to the seat back member, a lower arm adapted to be connected to the seat cushion member, a shaft member on which the upper and lower arms are rotatably supported and a lock mechanism which locks the upper and lower arms in position relative to each other and upon release allows the upper arm to be tilted in different angular positions with respect to the lower arm. A rotatable connecting shaft is connected to each of the shaft members by engaging elements provided on both the connecting shaft and the shaft members so that rotation of the connecting shaft causes rotation of the shaft members to effect release of the lock mechanisms. An operating lever is positioned at one side of the seat and is operatively connected to the connecting shaft so that operation of the operating lever causes rotation of the connecting shaft which in turn causes rotation of the shaft members to effect release of the lock mechanism.